Needle raising cams for circular knitting machines

ABSTRACT

A radially movable needle raising cam to be used in a circular knitting machine having a revolving needle cylinder and a circle of needles therein, the cam being movable radially inwardly of the cylinder during passage thereby of the low butts of a first group of needles in the cylinder, whereby the cam is in a position to engage the high butts of an adjoining group of needles in the cylinder to raise the latter needles. The forward end portion of the cam has its inner peripheral surface undercut provide an inner cam face adapted to engage the radially extending outer ends of the low butts of any of the first group of needles which may have had their butts inadvertently displaced radially outwardly, thereby to move the displaced needles and their butts radially inwardly of the cylinder. Such inward movement of the displaced needles prevents the raising thereof by the cam.

nited States ate 1191 Conti NEEDLE RAISING CAMS FOR CIRCULAR KNITTING MA [75] Inventor: Gianni Conti, Firenze, Italy [73] Assignee: G. Billi & Co. S.p.A., Firenge, Italy [22] Filed: Nov. 12, 1970 [21] 7 Appl. No.: 83,759

1,116,744 6/1968 GreatBritain ..'..66/50R Primary Examiner-Wm. Carter Reynolds Attorney-Louis Necho ABSTRACT A radially movable needle raising cam to be used in a circular knitting machine having a revolving needle cylinder and a circle of needles therein, the cam being movable radially inwardly of the cylinder during passage thereby of the low butts of a first group of needles in the cylinder, whereby the cam is in a position to engage the high butts of an adjoining group of needles in the cylinder to raise the latter needles. The forward end portion of the cam has its inner peripheral surface undercut provide an inner cam face adapted to engage the radially extending outer ends of the low butts of any of the first group of needles which may have had their butts inadvertently displaced radially outwardly, thereby to move the displaced needles and their butts radially inwardly of the cylinder. Such inward movement of the displaced needles prevents the raising thereof by the cam.

1 Claini, 2 Drawing Figures PATENTED 1 91975 v 3,726,110

INVENTCR GJANM CONTI I BY W 9 NEEDLE RAISING CAMS FOR CIRCULAR KNITTING MACHINES The present invention relates generally to the art of knitting and more particularly to an improvement in the formation of radially movable needle actuating cams for use in circular knitting machines, wherein the cams are adapted to actuate the needles of a first group of needles and to prevent the accidental actuation of any of the needles of a second and adjacent group thereof.

Circular knitting machines, particularly those used for the formation of ladies hosiery, have needles which are provided with butts of a plurality of varying lengths. The difference in length between successive butt lengths is relatively small in modern hosiery machines. The needles are arranged in groups in the needle cylinder of the machine according to their butt lengths with a first group of needles having butts of a first common length thereon and with a second group of needles having butts of a second and longer common length thereon. The machine is provided with a radially movable cam which, when properly positioned, is intended to engage only the longer butts of the second needle group to raise the same, and is not intended to engage any of the shorter butts of the needles of the second needle group which are intended to remain in their non-raised position.

However, due to the relatively small difference in length between the shorter and longer butts, and due to the fact that one or more of the shorter butts are generally outwardly displaced for one reason or another it is difficult to position the cam so that it will engage only the longer butts and will not engage the displaced shorter butts. When the shorter displaced butts are engaged by the cam, the needles associated therewith are raised, with the result that a flaw is made in the fabric being knit.

Accordingly, it is the principle object of the present invention to provide a radially movable needle-raising cam for use in a circular knitting machine wherein the cam will engage the longer butts of one group of needles to raise the same, and will prevent inadvertent needle-raising engagement between the cam and the shorter needle butts of displaced ones of another group of needles.

It is a further object of the present invention to provide a radially movable needle-raising cam for use in a circular knitting machine wherein the cam is adapted to engage the longer needle butts of one group of needles to raise the same, and is adapted to engage the shorter needle butts of displaced ones of another group of needles to move the same radially of the cylinder of the machine.

The above and other objects and advantages of the invention will be fully apparent hereinafter; it being understood that the present invention is primarily concerned with an improved radially movable needle-raising cam for use in circular knitting machines, all as will be described in detail, as shown in the accompanying drawings, and as set'forth in the appended claims.

IN THE DRAWINGS FIG. 1 is an elevational view of the inner faces of stitch and guard cams of a circular hosiery knitting machine, and of the inner face of the improved radially movable needle actuating cam of the present invention, as seen from inside the circle of needles and as taken on the line 1 1 ofFlG. 2.

FIG. 2 is a sectional view of FIG. 1 as taken along the line 2 2 thereof.

As illustrated in the drawings, a portion of the needle cylinder of a circular hosiery knitting machine is indicated at 1. The cylinder is provided on its outer side with a series of vertically extending slots 1A, within which a like series of lengthwise movable needles 3 are individually disposed. The needles are provided with butts of different lengths and are grouped according to their butt size, a first such group of needles having common length low or short butts 5A, while an adjacent second such group of needles have common length high or long butts 5B.

The needles 3 are moved lengthwise of their slots 1A by the action of appropriately shaped cams upon their butts 5A and 5B, and the needle cylinder, revolving in the direction of the arrow f1, moves the needles past relatively stationary needle-operating cams. A needlelowering stitch cam acting upon the butts 5A and 5B is shown at 7 in association with a guard cam 9 which prevents overthrow of the needles by the stitch cam and, which raises the needles slightly as the needles move on. Following the cams 7 and 9 is a radially movable needle-raising cam 10 of the present invention. The cam 10 has an inclined cam face 10A up which the needle butts 5B are adapted to be moved to the top of cam 10 when the latter is in proper radial position, as in FIG. 2.

According to the present invention, the cam 10 is modified so that its inner peripheral cam surface 10C is undercut adjacent the start of the cam rise 10A to provide the inner peripheral cam surface 108 which is thus spaced further from the needles than the remainder of the surface 10C. The depth of the undercut to form the cam face 108 is relatively very small and the cam face 108 extends from the forward end of the cam 10 to a point beyond the point of initial contact between the cam rise 10A and the butts 58, when the latter are being raised by the cam 10. The end of the cam face 108 is joined to the remainder of the cam face 10C along a vertically extending inner inclined cam face 1013.

The cam 10 is normally moved inwardly to its operative position of FIG. 2, in the direction of the arrow f3, during the passage thereby of the low butts 5A of a group of needles so as to be in position to engage the high butts 5B of a following group of needles to raise the same as the cylinder continues to revolve past the cam 10.

As may be seen in FIG. 2, when one or more of the needles having the low butts 5A are displaced outwardly from their normal position in the needle cylinder slots, their butts 5A are also outwardly displaced as shown at 5A1. Such displacement may result from the action of centrifugal force upon the needles or may be the result of needle misalignment. As low butts 5A move past the cam 10, the displaced butts 5A1 do not ride up the cam face 10A (which they would do in the absence of the present invention), but, instead, pass along the undercut face 108 until the inner cam 10E is reached, whereupon the cam 10E engages the outer ends of the butts 5A and moves the same radially inwardly of the needle cylinder. In this way the undesirable raising of displaced needles by the cam Ml is avoided.

Due to the undercut construction of cam 10, it may be moved to a position in which its face 10C just grazes, or makes contact with, the outer ends of butts 5A of the needles without any danger of the butts 5A being raised by the cam 10. Additionally, the improved cam may be spring-urged into operative position in such manner that its face 10C yieldingly presses against the outer ends of the low butts 5A wherein it will push in any displaced butts 5A1 and will be in position to positively engage and raise all of the butts 5B and their associated needles. The cam 10 may also be permitted to be spring-urged inwardly so that its face 10C yieldingly presses against the outer ends of the passing high butts 5B and, in such position, the undercut portion of the cam will prevent any of the high butts SE from riding up the cam face 10A. The cam 10 will then move further inwardly when it reaches the low butts 5A and thus will be in position to engage the next group of high butts 5B. Thus, the timing of the inward movement of the improved cam 10, as well as the extent of the movement itself, is much less critical in the operation of the machine.

While the present cam 10 is one that acts to raise the needles, it will be understood that the present invention is equally applicable to cams which act to lower needles. Also, that the cams of the present invention may be used upon the butts of jacks as well as upon the butts of needles.

What I claim is:

1. In a circular knitting machine of the type having a slotted needle cylinder and a circular series of needles individually disposed in and movable lengthwise of the slots in said cylinder, said needles having shank portions normally disposed in said slots and having butt portions projecting from said shank'portions to extend radially outwardly from the periphery of said cylinder, each of said butts having a horizontally extending edge and having a vertically extending edge at the end of said butt, a first group of said needles having butts of a first common length each of which normally extends a first common radial distance outwardly from the periphery of said needle cylinder, a second group of needles having butts of a second and longer common length each of which normally extends a second and longer common radial distance outwardly from the periphery of said needle cylinder, certain needles of said first group thereof at times having their butts extending radially outwardly beyond their normal position, the combination therewith of a cam spaced radially from said needle cylinder, means for moving said cam radially of said needle cylinder, an inclined surface on said cam engageable with the said horizontal edges of the butts of sald second needle group when said inclined surface of the cam is positioned in the path of said butts of the second needle group to move the needles of said second needle group upwardly along said inclined surface, a first inner curved surface on said cam extending peripherally about said needle cylinder, a second inner curved surface on said cam following said first curved surface and said second inner curved surface extending peripherally .about said needle cylinder said curved surfaces being unequally spaced radially mm the periphery of said needle cylinder with said first curved surface being spaced the greater distance therefrom, and a vertically extending inclined inner cam face joining the proximal portions of said first and second inner curved surfaces on said cam, said vertically extending inner cam face being adapted to engage the vertically extending edges of the butts of said certain of said first group of needles to move said certain needles radially inwardly of said slots to their normal position therein. 

1. In a circular knitting machine of the type having a slotted needle cylinder and a circular series of needles individually disposed in and movable lengthwise of the slots in said cylinder, said needles having shank portions normally disposed in said slots and having butt portions projecting from said shank portions to extend radially outwardly from the periphery of said cylinder, each of said butts having a horizontally extending edge and having a vertically extending edge at the end of said butt, a first group of said needles having butts of a first common length each of which normally extends a first common radial distance outwardly from the periphery of said needle cylinder, a second group of needles having butts of a second and longer common length each of which normally extends a second and longer common radial distance outwardly from the periphery of said needle cylinder, certain needles of said first group thereof at times having their butts extending radially outwardly beyond their normal position, the combination therewith of a cam spaced radially from said needle cylinder, means for moving said cam radially of said needle cylinder, an inclined surface on said cam engageable with the said horizontal edges of the butts of saId second needle group when said inclined surface of the cam is positioned in the path of said butts of the second needle group to move the needles of said second needle group upwardly along said inclined surface, a first inner curved surface on said cam extending peripherally about said needle cylinder, a second inner curved surface on said cam following said first curved surface and said second inner curved surface extending peripherally about said needle cylinder, said curved surfaces being unequally spaced radially from the periphery of said needle cylinder with said first curved surface being spaced the greater distance therefrom, and a vertically extending inclined inner cam face joining the proximal portions of said first and second inner curved surfaces on said cam, said vertically extending inner cam face being adapted to engage the vertically extending edges of the butts of said certain of said first group of needles to move said certain needles radially inwardly of said slots to their normal position therein. 